Income Taxes (Schedule Of Components Of Income Tax Expense) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current Income Tax Expense [Abstract]
Current federal income tax expense		$ 1,000	$ 1,144	$ 1,750
Current state income tax expense		254	287	235
Current foreign income tax expense		8	5	2
Total current income tax expense		1,262	1,436	1,987
Deferred Income Tax Expense [Abstract]
Deferred federal income tax expense (benefit)		417	344	(5,260)
Deferred state income tax expense		128	5	183
Deferred foreign income tax expense (benefit)		21	(10)	10
Total deferred income tax expense (benefit)	[1]	566	339	(5,067)
Total income tax expense (benefit)		$ 1,828	$ 1,775	(3,080)
Tax Cuts and Jobs Act of 2017, deferred tax liability, income tax expense (benefit) total				(5,935)
Tax Cuts and Jobs Act of 2017, federal income tax expense (benefit)				(5,965)
Tax Cuts and Jobs Act of 2017, state income tax expense (benefit)				$ 30

[1] 2017 includes a ($5,935) million adjustment to income tax expense resulting from the Tax Cuts and Jobs Act. Of this amount, ($5,965) million is a federal income tax benefit and $30 million is state income tax expense.